Xilinx, Inc.

Zilog, Inc.

Ross H Freeman

Hung-Cheng Hsieh

This invention provides additional circuitry for a configurable logic array having logic functions which are programmed by loading memory cells which cause the logic array to generate a desired function. With the additional circuitry, the memory cells can also be used as memory for access by other parts of the logic array during operation.

Circuit for selecting a bit in a look-up table

Distributed memory architecture for a configurable logic array and

Additional circuitry for a configurable logic array having logic functions which are programmed by loading memory cells which cause the logic array to generate a desired function. With the additional circuitry, the memory cells can also be used as memory for access by other parts of the logic array during operation.

A configurable logic array comprises a plurality of configurable logic elements variably interconnected in response to control signals to perform a selected logic function. Each configurable logic element in the array is in itself capable of performing any one of a plurality of logic functions depending upon the control information placed in the configurable logic element. Each configurable logic element can have its function varied even after it is installed in a system by changing the control information placed in that element. Structure is provided for storing control information and providing access to the stored control information to allow each configurable logic element to be properly configured prior to the initiation of operation of the system of which the array is a part. Novel interconnection structures are provided to facilitate the configuring of each logic element.

Configurable electrical circuit having configurable logic elements and

A technique for programming connections of conductors that is particularly adapted to be implemented as part of an integrated circuit so that a number of connections internal of the circuit can be made from outside the circuit in order to customize it after fabrication. A specific arrangement of five switching transistors is particularly advantageous for each cross-point of two conductors to be connected together in one of many possible ways. The desired switching arrangement at each cross-point may be programmed by use of the same conductors being interconnected to carry control signals from outside the circuit to a memory associated with each cross-point switching circuit. While these memories are being programmed, each cross-point is temporarily forced to a desired state for communicating the control signals from outside the circuit to the memories.

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San Jose, CA, United States of America

Ross H Freeman